1. Field of the Invention
The present invention relates to an emergency protective circuit device and, more particularly, to an electronic current limiter that limits a load current (or power) of an illuminating lamp.
2. Description of the Related Art
An electronic current limiter is used to limit a load current (or power) of an illuminating lamp to prevent the illuminating lamp from being burnt or worn out due to an excessive load current. The control circuit structure of the conventional electronic current limiter comprises a sampling circuit, a rectification filter circuit, an amplification comparison circuit and an output control circuit. The amplification comparison circuit includes a current transformer, a comparator, a silicon control rectifier (SCR) and a relay. When the load current of the illuminating lamp exceeds a predetermined value, the relay is actuated by the silicon control rectifier to turn off the illuminating lamp to prevent the illuminating lamp from being burnt or worn out due to an excessive load current. However, the conventional electronic current limiter has a complicated construction, an unstable performance, lower precision and reliability and a higher cost of maintenance.